1. Field of the Invention
The present invention relates to a display apparatus, and more particularly to a projection apparatus, a light source module, and a beam combiner.
2. Description of Related Art
FIG. 1 is a schematic view of a conventional beam combiner. Referring to FIG. 1, a conventional beam combiner 100 includes a red reflecting mirror 110a and a blue reflecting mirror 110b. A blue beam L10c emitted by a blue light source 50c is reflected by the blue reflecting mirror 110b. A red beam L10a emitted by a red light source 50a is reflected by the red reflecting mirror 110a, and mixes with the blue beam L10c. A green beam L10b emitted by a green light source 50b passes through the red reflecting mirror 110a and the blue reflecting mirror 110b, and mixes with the red beam L10a and the blue beam L10c. 
FIG. 2 is a schematic view of another conventional beam combiner. Referring to FIG. 2, a conventional beam combiner 200 includes a red prism 210a, a green prism 210b, and a blue prism 210c. The red prism 210a has a red reflecting surface 212a, and the blue prism 210c has a plurality of blue reflecting surfaces 212c. The blue beam L10c emitted by the blue light source 50c is reflected by the blue reflecting surfaces 212c. The red beam L10a emitted by the red light source 50a is reflected by the red reflecting surface 212a, and mixes with the blue beam L10c. The green beam L10b emitted by the green light source 50b passes through the red reflecting surface 212a and the blue reflecting surfaces 212c, and mixes with the red beam L10a and the blue beam L10c. 
The beam combiner 100 is required to have a plurality of reflecting mirrors, so the volume of the beam combiner 100 cannot be reduced. The beam combiner 200 has a plurality of prisms, and the processes of the prism are complex, and thus the manufacturing cost of the beam combiner cannot be reduced.